Thursday, 2 June 2016

I get a lot of questions about which lens to use and why, also what are the differences between focal lengths and why use one over another.
So to try and explain I have done a series of shots using 5 different lenses 2 zooms and 3 primes.
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The first 5 shots are all taken from the same spot 4 feet away from ZENA (the warrior princess, don't worry she's armless) with the 70 - 200 mm zoom. The major difference from the 70 mm shot (first) to the 200 mm shot (last) is that the frame gets progressively full of the face with no distortion the closer you get. The focal lengths from the first image to the fifth is as follows: 70,85,105,135,200.

The 5 above show the results from the 24 - 85 mm zoom. You will notice that, as the point of view and distance do not change, the relationship with the background also does not change other than you can see more of it the wider you go. The focal lengths from the first to the fifth are as follows: 24,35,50,70,85.
Apart from a slight quality change there are few differences when using the prime from 35, 50 and 85 mm shown below.

The next series of 13 images below are taken with the same settings and lenses, but this time I am trying to get Zena the same size in the frame each time, which means I have to start a long way back with the 200 mm. and slowly move closer to the subject each time I change focal length to a wider one, 24 mm. The differences are, that the relationship between the background and the subject changes as does the distortion of the face, the background distance seems to get compressed the longer the lens you use, and getting closer to the subject with the wider lens brings the foreground closer to the lens which makes the nose bigger and everything else radiating from that point gets progressively smaller. which can be clearly seem from the first image taken with the 24 mm focal length at a very close distance from Zena.

The focal lengths are as follows: 24,35,50,70,85. Then 70,85,105,135,200.

The last 3 above are with the primes from 35, 50 and 85 mm.
I trust this helps a little if not and you need more clarification let me know.